The choice of power cable conductor, it has been through copper, aluminum, iron, nickel, silver, gold and so on, but the practice has proved: copper and aluminum is the most suitable material carrying current, is currently the main choice of wire and cable in the world. Gold, silver and silver nickel alloys are used only in a small amount, mainly in integrated circuit boards, relay contactors and circuit breaker contacts and aerospace.
Due to the low quality of aluminum alloy cable, it is especially suitable for the cable laying of buildings with large span, such as sports venues and exhibition centers.
In addition, the high-rise building, the use of aluminum alloy cable can reduce the difficulty of the vertical cable laying and workload, save labor costs, but also reduced due to the cable could cause body injury risk during construction.
Since the melting point of aluminum is 660, it is necessary to choose a special fireproof cable (new flexible mineral insulated cable) for the fire line that needs continuous power supply in disaster relief.
Cable laying channel resources are also one of the main costs of cable construction and operation. Urban power grid is nearly half of the cable pipe laying, choose aluminum alloy cable when in the exhaust pipe, the exhaust pipe diameter larger than choose copper core cable aperture to two specifications or using two tube hole, so choose aluminum alloy cable increased exhaust pipe construction and running costs.
Increasing the cross-section of other laying methods will also increase land cover and increase construction and operating costs.
The power cable is installed in the installation. Each bend in a different direction tensile force, the dynamic pressure and to produce cable damage, and cable laying produced during the installation drawing of dynamic pressure is much bigger than the cable stops, so in each case, the bending radius of the cable should be larger.
In meet the under the premise of carrying capacity and energy loss, the direct costs of the aluminum alloy cable is cost is lower than copper cable ontology, that is, because of the aluminium alloy cables of copper core cable is light in weight and more suitable for aluminum alloy cable of large span buildings, can greatly reduce the load of construction steel structure, save the cost of steel structure.
In addition, it can reduce the difficulty and workload of vertical laying cable for high-rise buildings. In some low-voltage distribution systems, the cable channel resources are abundant, and there are not many places for parallel laying of cables.
However, with the development of urban distribution network, the load density becomes higher and higher, and the number density of cable laying in cable channel increases accordingly. For shortage of cable channel resources, short circuit current big occasions when choosing aluminum alloy cable will not be able to consider only the direct costs of the aluminum alloy cable, consider comprehensive cost, even if choose aluminum alloy cable increased the size of the cable channels, too close for laying makes flow with reduced with the decrease of the cable spacing, capacitive current increase the need to increase the arc suppression coil capacity building and running cost, etc.
In addition, the maximum allowable short-circuit temperature and the thermal stability coefficient of the aluminum alloy cable are lower than that of copper core cable, and the thermal stability check should be carried out during the design to ensure the safe and reliable operation of the power grid.